The invention relates to the use of alkyl glycidyl ether-capped diamines as foam controlling agents.
Foam control or elimination in many waterborne applications and industrial processes is critical for obtaining optimal performance in application and high process efficiency [R. Hxc3x6fer and coworkers, in B. Elvers, J. F. Rounsaville and G. Schulz, eds., Ullmann""s Encyclopedia of Industrial Chemistry, Vol. A11, 5th Ed., VCH Publishers, New York, 1988, p. 466-488]. Foam problems can arise during production, processing and application. The importance of foam control and elimination is well-appreciated in applications such as waterborne coatings, inks, adhesives, lubricants, over-print varnishes and agricultural formulations and in industrial processes such as oil well drilling, completion and production, acid gas scrubbing, food processing, pulp and paper processing, fermentation, metal treatment, polymer and chemical synthesis, waste-water treatment and textile dying.
Undesirable foam can lead to inefficient mixing, poor productivity, reduced vessel capacity and equipment failure in many common industrial processes. For instance, foaming in refinery processes such as drilling, completion, production, distillation, extraction, gas and liquid scrubbing and other operations leads to a number of operating difficulties and significant economic consequences. In acid gas sweetening, or scrubbing, gases such as carbon dioxide and hydrogen sulfide are removed via scrubbing with an aqueous amine solution. Problematic foam can occur during both the scrubbing or regeneration steps in this process [V. E. Lewis and W. F. Minyard, Antifoaming and Defoaming in Refineries in Foams: Fundamentals and Applications in the Petroleum Industry, Adv. Chem. Ser., 1994, 242, p 461-483].
Defoamers and antifoams are additives that are used to reduce or eliminate problematic foam. An xe2x80x9cantifoamxe2x80x9d refers to a long-acting additive which prevents foam formation. A xe2x80x9cdefoamerxe2x80x9d is an additive that yields rapid knock-down of existing foam thereby reducing or eliminating the foam. Herein, the term xe2x80x9cfoam control agentxe2x80x9d is used to refer to additives that prevent and/or control foam since many applications and processes require both foam prevention and reduction or elimination.
Foam control agents act to prevent or eliminate foam by countering foam stabilizing forces and accelerating the rate of foam film drainage. Conventional foam control agents utilized in waterborne systems include silicones, dispersed hydrophobic solids, hydrocarbon fluids and polyalkyleneoxide polymers.
In many applications, foam control agents exhibit positive ancillary surface properties, such as wetting, dispersion, emulsification, solubilization, flow and leveling. For example, defoamers and antifoams that act as wetting agents will greatly reduce surface defects in coatings, inks, adhesives, over-print varnishes and agricultural formulations. In addition, such multi-functional materials will allow for the reduction or elimination of wetting agents in a waterborne composition, thereby reducing the total amount of additives. The ability of a material to act as a wetting agent in waterborne formulations is assessed by its ability to reduce the surface tension of water. Equilibrium surface tension performance is important when a system is at rest. However, the ability to reduce surface tension under dynamic conditions is of great importance in applications where high surface creation rates are utilized. Such applications include the spraying, rolling and brushing of coatings, adhesives or agricultural formulations, or high-speed gravure or ink jet printing. Dynamic surface tension is a fundamental quantity which provides a measure of the ability of a substance to reduce surface tension and provide wetting under high-speed application conditions. Also, the entrainment of air and the creation of foam is a problem under high-speed application conditions.
In addition to the development of multi-functional foam control agents, there is considerable interest in the industry in foam control agents with improved environmental characteristics. This increased environmental concern has been, in part, due to the poor environmental characteristics of currently used foam control agents and new environmental regulations. Such negative characteristics include poor biodegradation, a potential to bioaccumulate and high aquatic toxicity. Thus, not only is it desirable to obtain foam control agents which provide excellent foam prevention or elimination and dynamic wetting, but it is also highly desirable that such new materials are environmentally-friendly.
Highly effective foam control agents, which contain 100 percent active ingredient, have low color and low odor characteristics, can be used effectively under a wide range of operating conditions and do not adversely affect formulation performance or result in the disruption of downstream processes, are highly desirable. Moreover, there is a need in the industry for antifoaming and defoaming agents that exhibit positive ancillary surface properties, such as wetting, dispersion, emulsification, solubilization, flow and leveling.
Foam control agents are widely used in polymer production and processing since foam can lead to reduced production capacity, efficiency and equipment problems. In particular, severe foaming problems commonly result upon stripping unreacted monomers from the polymer product [H. F. Mark, N. M. Bikales, C. G. Overberger, G. Menges and J. I. Kroschwitz, Eds., Encyclopedia of Polymer Science and Engineering, 2nd Ed. Vol 2, John Wiley and Sons, New York, 1985, p. 59].
Selection of an appropriate foam control agent is key to the successful production, transfer and application of waterborne coatings, inks and adhesives. Defoamers are required in most waterborne coating formulations since they contain wetting agents, emulsifiers, dispersants and other additives which are capable of stabilizing foam [R. A. Reinhardt et. al., Defoamer Selection in Waterborne Coatings, Journal of Coatings Technology, 1998, 70, 157]. Problematic foam can lead to gloss and color loss, craters, pinholes, fish-eyes, orange peel, crawling, poor recoatability, poor color acceptance, adhesion loss and haze development.
U.S. Pat. No. 4,650,000 discloses that cationic quaternary ammonium salts of the adducts of diamines and C8-C18 alkyl glycidyl ethers are effective surfactants for the formation of microemulsions containing a hydrocarbon oil and aqueous acid solutions used to treat subterranean rock formations surrounding oil and gas wells.
U.S. Pat. No. 4,797,202 discloses N-(hydrocarbyl)-xcex1,xcfx89-alkanediamines as collectors for the recovery of minerals from mineral ores by froth flotation. In particular, the 1:1 adduct of ethylenediamine and butyl glycidyl ether was shown to be effective for copper recovery in the froth flotation of copper sulfide.
CH 313159 discloses a process for the preparation of stable dye and stripper baths containing positively charged amine additives. The baths contain 1:1 adducts of diamines and polyamines and C8 and greater alkylglycidyl ethers and the corresponding alkylated amines formed by subsequent reactions with ethylene oxide, dimethyl sulfate, chloroacetic acid and other reagents.
JP 2001-107083 discloses 1:1 adducts of amines and alkyl glycidyl ethers for use in laundry detergent compositions.
JP 450119973 discloses adducts prepared by the reaction of amines and C6 to C16 alkyl glycidyl ethers as effective bactericidal surfactants. These compounds all contain carboxylate groups.
JP 200010268 discloses the use of adducts containing ethylenically unsaturated groups in photosensitive pastes. In particular, adducts of diamines and glycidyl methacrylate were used.
U.S. Pat. No. 3,931,430 discloses a method for using the reaction products of diamines and polyamines and C4-C16 glycidyl esters and ethers as desensitizers for pressure-sensitive recording sheets. These desensitizers must be soluble in the oil vehicle used to make non-aqueous inks for offset printing.
The present invention pertains to a method for controlling the foaming of a waterborne composition or in an industrial process utilizing a waterborne composition by the incorporation of a foam controlling agent in an amount effective for controlling foam. The method comprises utilizing as the foam controlling agent an alkyl glycidyl ether-capped diamine compound of the formula: 
L is a linker group comprising a linear, branched, or cyclic alkyl group having from 2 to about 6 carbon atoms or an alkyl ether group having from about 4 to about 8 carbon atoms. R is independently selected from hydrogen or xe2x80x94CH2CHOHCH2ORxe2x80x2. Rxe2x80x2 is an alkyl group having from about 4 to about 22 carbon atoms. The compound generates an initial foam height at least 30% less than a 0.1 wt % aqueous solution of dioctyl sodium sulfosuccinate (DOSS), when added at 0.1 wt % to the aqueous DOSS solution.
Another embodiment of the invention comprises an alkyl glycidyl ether-capped diamine compound which comprise ethylenediamine capped, or adducted, with from 3 or 4 iso-butyl glycidyl ethers and di(aminopropyl)diethylene glycol capped with from 1 to 4 n-butyl glycidyl ethers.
The present invention also pertains to an aqueous composition comprising a foam controlling agent. The composition manifests greater foaming in the absence of the foam controlling agent. The foam controlling agent is an alkyl glycidyl ether-capped diamine present in an amount effective for controlling foam and has the formula: 
wherein L, R, and Rxe2x80x2 are as defined above.
This invention relates to the use of the reaction products of diamines and alkyl glycidyl ethers for controlling, i.e. reducing, preventing or eliminating, foam in waterborne compositions and industrial processes that otherwise manifest foaming. There are significant advantages associated with the use of these alkyl glycidyl ether-capped diamines as foam control agents in water-based compositions and processes. These advantages include: foam control agents which have low odor and color; foam control agents which contain 100 percent active ingredient and thus do not require carrier fluids, solvents or other additives and exhibit improved shelf stability; waterborne coatings and inks which have low volatile organic content, thus making these formulations environmentally favorable; foam control agents capable of reducing the dynamic surface tension of waterborne compositions; waterborne coatings, inks, adhesives and agricultural formulations which may be applied to a variety of substrates with excellent wetting of substrate surfaces including contaminated and low energy surfaces; a reduction in coating or printing defects such as orange peel and flow/leveling deficiencies in comparison to conventional foam control agents; waterborne compositions capable of high speed application and processing; and industrial processes which have no foam or greatly reduced amounts of problematic foam with a reduction in negative effects in down-stream applications.
Not all alkyl glycidyl ether-capped diamines are capable of significantly reducing or eliminating foam. Therefore, the correct combination of diamine and alkyl glycidyl ether and an optimum degree of adduction is essential for the reduction and/or elimination of foam. Thus, suitable alkyl glycidyl ether-capped diamines are those that generate an initial foam height at least 30% less than a 0.1 wt % aqueous solution of dioctyl sodium sulfosuccinate (DOSS) when added at 0.1 wt % to the aqueous DOSS solution, as measured according to ASTM D 1173-53 at ambient temperature.
The terms xe2x80x9cwater-basedxe2x80x9d, xe2x80x9cwaterbornexe2x80x9d, xe2x80x9caqueousxe2x80x9d or xe2x80x9caqueous mediumxe2x80x9d, for the purposes of this invention, mean a solvent or liquid dispersing medium which comprises water, preferably at least 90 wt %, and most preferably at least 95 wt %, water. Obviously, an all water medium is also included.
In another embodiment of the invention, the foam control agents may be utilized as wetting agents. It is desirable that an aqueous solution of the foam control agents exhibit ancillary wetting properties, as demonstrated by a dynamic surface tension xe2x89xa645 dynes/cm at a concentration of xe2x89xa61 wt % in water at 25xc2x0 C. and 0.1 bubble/second according to the maximum-bubble pressure method. The maximum-bubble-pressure method of measuring surface tension is described in Langmuir 1986, 2, 428-432, which is incorporated by reference.
The excellent defoaming and antifoaming properties of these foam control agents suggest that these agents will be useful in applications and processes in which the reduction, prevention or knock-down of foam are important. Such applications include coatings, inks, adhesives, agricultural formulations, oil well production, acid gas scrubbing of a gas stream, for example, petroleum or natural gas, food processing, pulp and paper processing, fermentation, metal treatment, polymer and chemical synthesis, waste-water treatment and textile dying and finishing. As used in this specification and the appended claims, xe2x80x9coil well productionxe2x80x9d is intended to comprise the drilling, completion, i.e., cementing, and/or pumping of the crude oil, as opposed to the stimulation of the oil well by treatment of formations surrounding the well. A preferred embodiment of the invention comprises a process for the removal of hydrogen sulfide and/or carbon dioxide from an acid gas-containing gas stream, such as natural gas, wherein the gas stream is contacted with an aqueous amine solution to adsorb the hydrogen sulfide, the aqueous amine solution is optionally regenerated, and an alkyl glycidyl ether-capped diamine according to the invention is added to control foam.
In addition, these materials can reduce the dynamic surface tension of waterborne compositions. Such attributes allow these materials to be used to control and eliminate foam with significantly less deleterious effects in application, making them extremely useful in coatings, inks and adhesives. Moreover, the wetting ability of these foam control agents allows these materials to be utilized in polymer production and processing without defects in downstream applications. In addition, such multi-functional materials will allow for the reduction or elimination of wetting agents in a waterborne composition, thereby reducing the total amount of additives.
From the data included in the examples, is evident that not all alkyl glycidyl ether-capped diamines are capable of reducing or eliminating foam and that certain adducts in fact add problematic foam to waterborne systems. Therefore, the correct combination of diamine and alkyl glycidyl ether group and an optimum degree of adduction as demonstrated in this work is essential for the reduction and/or elimination of foam. It is also unexpected that the foam control agents of this invention exhibit improved biodegradation in comparison to the corresponding adducts prepared from polyamines and alkyl glycidyl ethers.
In accord with the present invention, a method is provided for controlling the foaming of a waterborne composition or an industrial process by the incorporation of a foam controlling agent in an amount effective for controlling foam. The method comprises utilizing as the foam controlling agent an alkyl glycidyl ether-capped diamine compound of the formula: 
The alkyl glycidyl ether-capped diamine compounds of the present invention generate an initial foam height at least 30% less than a 0.1 wt % aqueous solution of dioctyl sodium sulfosuccinate (DOSS), when added at 0.1 wt % to the aqueous DOSS solution. Preferably, the compound generates an initial foam height 40%, and more preferably 50%, less than a 0.1 wt % aqueous solution of dioctyl sodium sulfosuccinate.
In the alkyl glycidyl ether-capped diamine compounds, L is a linker group comprising a linear, branched, or cyclic alkyl group having from 2 to about 6 carbon atoms or an alkyl ether group having from about 4 to about 8 carbon atoms. Preferably, L is an alkyl group having from about 2 to about 5 carbon atoms, more preferably from about 2 to about 4 carbon atoms, and most preferably from 2 to 3 carbon atoms. Preferably, L is an alkyl ether group having from about 4 to about 10 carbon atoms, more preferably from about 10 carbon atoms.
R is independently selected from hydrogen or xe2x80x94CH2CHOHCH2ORxe2x80x2. Rxe2x80x2 may be an alkyl group having from about 4 to about 22 carbon atoms. Preferably, Rxe2x80x2 is an alkyl group having from about 4 to about 20 carbon atoms, more preferably from about 4 to about 16 carbon atoms, and most preferably from about 4 to about 12 carbon atoms.
In a specific embodiment, L is xe2x80x94CH2CH2xe2x80x94, R is independently selected from hydrogen or xe2x80x94CH2CHOHCHOxe2x80x94CH2CH2CH2CH3, i.e., Rxe2x80x2 is a butyl group. In another specific embodiment, L is xe2x80x94CH2CH2xe2x80x94, R is independently selected from hydrogen or xe2x80x94CH2CHOHCHOxe2x80x94CH2CH(CH3)2, i.e., Rxe2x80x2 is an iso-butyl group. Preferably, there are from 2 to 4 capping groups on the amine, i.e., the ratio of amine to alkyl glycidyl ether in the epoxide opening reaction is from about 1:2 to about 1:4.
In another embodiment, the present invention is directed to an aqueous composition comprising a foam controlling agent, which composition manifests greater foaming in the absence of the foam controlling agent. The foam controlling agent is an alkyl glycidyl ether-capped diamine present in an amount effective for controlling foam and has the formula: 
wherein L, R, and Rxe2x80x2 are as defined above.
In a specific embodiment, the waterborne composition is a protective or decorative coating; an ink composition; an adhesive composition; an overprint varnish; a radiation cured coating, ink, overprint varnish, or adhesive composition; an agricultural composition; or an acid gas scrubbing composition. In another specific embodiment, the industrial process is oil well production, acid gas scrubbing, food processing, pulp or paper processing, fermentation, metal treatment, polymer or chemical synthesis, waste-water treatment, or textile dyeing or finishing.
The alkyl glycidyl ether-capped diamines of the invention may be prepared by the reaction of a diamine with one or more alkyl glycidyl ethers in an epoxide ring opening reaction. The reaction may be performed with or without solvent. Preferably, the alkyl glycidyl ether is added to the amine reagent and the reaction temperature is maintained between 60-120xc2x0 C. The product may be used with or without purification. The product obtained from the reaction of a diamine and an alkyl glycidyl ether is a mixture since the hydroxy group generated via the epoxide ring opening reaction may also react with an alkyl glycidyl ether. The reaction illustrated below shows one of the more common adducts contained in the product mixture: 
where L, R and Rxe2x80x2 are as defined above.
All alkyl glycidyl ethers or mixtures of alkyl glycidyl ethers containing the requisite number of carbon atoms (C4 to C22) may be utilized for the preparation of the capped-diamine foam control agents of this invention. Alkyl groups which are suitable should have sufficient carbon atoms to confer surface activity, i,e., an ability to act as a foam control agent and reduce the surface tension of water.
The alkyl groups in the alkyl glycidyl ether-capped diamines of this invention may be the same or different. Examples of suitable linear or branched alkyl glycidyl ethers (CH2(O)CHxe2x80x94CH2ORxe2x80x2) include butyl glycidyl ether, isobutyl glycidyl ether, pentyl glycidyl ether, iso-amyl glycidyl ether, hexyl glycidyl ether, 2-ethylhexyl glycidyl ether, octyl glycidyl ether, decyl glycidyl ether, lauryl glycidyl ether, myristyl glycidyl ether, cetyl glycidyl ether, and the like.
Examples of suitable diamines (H2Nxe2x80x94Lxe2x80x94NH2) include those with linear, branched and cyclic hydrocarbon spacers, such as ethylenediamine, propylenediamine, butanediamine, pentanediamine, hexamethylenediamine, 2-methyl-1,5-pentanediamine and bis (p-amino-cyclohexyl) methane. In addition, suitable diamines may contain ether moieties in the spacer group. Optimal performance for a specific application can be achieved be appropriate manipulation of the starting amine and alkyl glycidyl ether and the degree of adduction.
The amount of alkyl glycidyl ether-capped diamine that is effective to reduce or eliminate the foam of the water-based, organic compound-containing composition is an amount effective for controlling foam. In general, this amount may range from about 0.001 to about 20 g/l 100 mL, preferably from about 0.01 to about 10 g/l 100 mL, of the aqueous composition. Naturally, the most effective amount will depend on the application and the efficiency of the foam control agent.
The alkyl glycidyl ether-capped diamines are suitable for use in an aqueous composition comprising in water an inorganic or organic pigment, a polymerizable monomer, such as addition, condensation and vinyl monomers, an oligomeric resin, a polymeric resin, a herbicide, a fungicide, an insecticide, or a plant growth modifying agent.
In a specific embodiment, the composition comprises in water an inorganic compound which is a mineral ore or a pigment or an organic compound which is a pigment, a polymerizable monomer, such as an addition, condensation or vinyl monomer, an oligomeric resin, a polymeric resin, a herbicide, an insecticide, a fungicide, or a plant growth modifying agent.
The alkyl glycidyl ether-capped diamines of the present invention may be employed along with conventional additives in water-based protective or decorative organic coatings, inks, adhesives, fountain solutions, agricultural, varnish, and acid gas sweetening compositions.
A typical water-based coating formulation to which the foam control agents of the invention may be added would comprise the following components in an aqueous medium at 30 to 80% xe2x80x9csolidsxe2x80x9d, i.e., listed ingredients:
(a) 0 to 50 wt % of a pigment dispersant/grind resin;
(b) 0 to 80 wt % of coloring pigments/extender pigments/anti-corrosive pigments/other pigment types;
(c) 5 to 99.9 wt % of water-borne/water-dispersible/water-soluble resins;
(d) 0 to 30 wt % of slip additives/antimicrobials/processing aids;
(e) 0 to 20 wt % of coalescing or other solvents;
(f) 0.01 to 10 wt % of surfactant/wetting agent/flow and leveling agents; and
(g) 0.01 to 5 wt % of an alkyl glycidyl ether-capped diamine foam control agent.
A typical water-based ink composition to which the foam control agent of the invention may be added would comprise the following components in an aqueous medium at 20 to 60% xe2x80x9csolidsxe2x80x9d, i.e., listed ingredients:
(a) 1 to 50 wt % of a pigment;
(b) 0 to 50 wt % of a pigment dispersant/grind resin;
(c) 0 to 50 wt % of a clay base in appropriate resin solution vehicle;
(d) 5 to 99.9 wt % of water-borne/water-dispersible/water-soluble resins;
(e) 0 to 30 wt % of coalescing solvents;
(f) 0.01 to 10 wt % of a surfactant/wetting agent;
(g) 0.01 to 10 wt % of processing aids/solubilizing agents;
(h) 0.01 to 5 wt % of an alkyl glycidyl ether-capped diamine foam control agent.
A typical water-based agricultural composition to which the foam control agent of the invention may be added would comprise the following components in an aqueous medium at 0.01 to 80% xe2x80x9csolidsxe2x80x9d, i.e., listed ingredients:
(a) 0.1-50 wt % of a pesticide or plant growth modifying agent;
(b) 0 to 5 wt % of a dye;
(c) 0 to 20 wt % of a thickener/stabilizer/co-surfactant/gel/Inhibitor;
(d) 0 to 25 wt % of an antifreeze;
(e) 0.01 to 50 wt % of a surfactant/wetting agent;
(f) 0.01 to 10 wt % of an alkyl glycidyl ether-capped diamine foam control agent.
A typical fountain solution composition for planographic printing to which the foam control agent of the invention may be added would comprise the following components:
(a) 0.05 to 10 wt % of a film formable, water soluble macromolecule;
(b) 1 to 25 wt % of an alcohol, glycol, or polyol with 2-12 carbon atoms;
(c) 0.01 to 20 wt % of a water soluble organic acid, inorganic acid, or a salt thereof;
(d) 30 to 70 wt % of water;
(e) 0.01 to 5 wt % of a wetting agent; and
(f) 0.01 to 5 wt % of an alkyl glycidyl ether-capped diamine foam control agent.
A typical pressure sensitive adhesive to which the foam control agent of the invention may be added would comprise the following components:
(a) 50 to 99 wt % of an acrylic copolymer emulsion or SBR/natural rubber latex;
(b) 0 to 50 wt % of a tackifier dispersion;
(c) 0 to 5 wt % of a rheology modifier;
(d) 0 to 10 wt % of water;
(e) 0.1 to 5 wt % of a wetting agent;
(f) 0.1 to 5 wt % of an alkyl glycidyl ether-capped diamine foam control agent.
A typical pressure overprint varnish to which the foam control agent of the invention may be added would comprise the following components:
(a) 20 to 80 wt %of a water-borne/water dispersible resin;
(b) 0 to 20 wt % of a wax;
(c) 2 to 50 wt % of water;
(d) 0 to 20 wt % of a biocide/optical brightener/crosslinker/scuff and water resistant additive;
(e) 0 to 20 wt % of a co-solvent;
(f) 0.01 to 5 wt % of a wetting agent;
(g) 0.1 to 5 wt % of an alkyl glycidyl ether-capped diamine foam control agent.
A typical acid gas scrubbing composition to which the foam control agent of the invention may be added would comprise in water 10 to 70 wt % of at least one amine, preferably an alkanolamine, as is well known in the art and 1 to 500 ppm of an alkyl glycidyl ether-capped diamine foam control agent.
The present invention can be further illustrated by the following examples of preferred embodiments thereof, although it will be understood that these examples are included merely for purposes of illustration and are not intended to limit the scope of the invention unless otherwise specifically indicated.